Research On Long-term Coherent Accumulation Of High-speed Maneuvering Target

With the development of stealth technology,the radar cross-sectional area of modern stealth aircraft is very small,so that the received radar echo is submerged in noise and clutter.The most direct way to improve the radar’s ability to detect weak targets is to increase the radar’s staring time.However,for high-speed maneuvering target echo,range unit walking and Doppler spread will occur,resulting in prolonging coherent accumulation time and unable to obtain higher signal-to-noise ratio gain.Based on the above problems,this paper studies the range element walking and Doppler spread in the coherent accumulation of high-speed maneuvering targets.This paper studies the Linear Frequency Modulation signal commonly used in pulse radar,and introduces the classical algorithm for echo accumulation of high-speed moving targets.According to the motion state of the target,based on Wigner-Ville distribution(WVD),this paper proposes second-order WVD(SWVD)algorithm and third-order WVD algorithm respectively(TWVD)algorithm is used to estimate the echo phase parameters.For the target with uniform acceleration along the radar radial direction,the keystone transform is used to correct the distance walk of the target echo,the echo is modeled as LFM signal along the slow time,and the matrix is constructed according to the SWVD algorithm to transform the signal to the slow time domain delay time frequency domain plane along the slow time dimension After the degree superposition accumulation,the target motion parameters are extracted,and the compensation factor is constructed according to the estimated motion parameters to complete the Doppler spread compensation.For the target moving with uniform acceleration in any direction,the range unit walk correction is completed through the second-order keystone transform and Hough transform,the echo is modeled as QFM signal along the slow time,the matrix is constructed according to the TWVD algorithm,the signal is converted to the timefrequency domain plane for cubic phase parameter estimation,and finally the complete compensation of echo Doppler spread is realized.SWVD and TWVD algorithms can estimate the phase parameters without parameter search,and the algorithm complexity is low,so they have broad application prospects.Simulation results show that SWVD and TWVD algorithms have good anti noise and cross term interference ability,and can effectively estimate the motion parameters of the target.For the parameter estimation of higher-order phase polynomials,Based on TWVD algorithm,a generalized form of higher-order WVD is proposed in this paper(Ho WVD),by introducing multi-order delay time variables into high-order phase polynomials,a highdimensional matrix is constructed to realize the complete decoupling of slow time and delay time,and finally estimate all phase parameters iteratively.For the problem that Ho WVD matrix occupies too much storage resources,this paper also proposes a method to reduce its resource consumption.The simulation results show that the algorithm can effectively estimate the order parameters of higher-order phase polynomials.